| 1. |
- Aryal, Nabin, et al.
(författare)
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Coupling of microbial electrosynthesis with anaerobic digestion for waste valorization
- 2020
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Ingår i: Advances in Bioenergy. - : Elsevier. ; , s. 101-127
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Bokkapitel (refereegranskat)abstract
- Anaerobic digestion (AD) has been widely applied bioprocess to produce the biogas for fuels from organic waste degradation. AD has been integrated with other processes for increasing the digestion efficiency and waste valorization. The integration of AD with other bioprocess optimizes the production of targeted product and reduces the waste. Recently, microbial electrosynthesis (MES) was coupled with AD for the biomethane production, chemical synthesis and resource recovery. MES coupling to AD also gives an opportunity for value-added chemical generation and hence provides additional economic gains of integrated system. In MES, the remaining carbon dioxide (CO2) in biogas is reduced to methane by methanogens utilizing in situ produced hydrogen at cathode, thereby enriching methane content. Furthermore, electroactive microbes could directly accept the electron from cathode to reduce the CO2 to methane and chemicals. Therefore, CO2 fraction in the biogas could be utilized for the further chemical synthesis such as acetate, butyrate. In this chapter, advances on AD technology and MES coupling with AD are thoroughly discussed for the production of fuels and chemicals. The outputs of recent laboratory scale experiments are summarized and discussed. Furthermore, mechanism of CO2 reduction is elaborated with methane and chemical production.
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| 2. |
- Aryal, Nabin, et al.
(författare)
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Microbial electrochemical approaches of carbon dioxide utilization for biogas upgrading
- 2022
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 291:Part 1
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Tidskriftsartikel (refereegranskat)abstract
- Microbial electrochemical approach is an emerging technology for biogas upgrading through carbon dioxide (CO2) reduction and biomethane (or value-added products) production. There are limited literature critically reviewing the latest scientific development on the Bioelectrochemical (BES) based biogas upgrading technology, including CO2 reduction efficiency, methane (CH4) yields, reactor operating conditions, and electrode material tested in BES reactor. This review analyzes the reported performance and identifies the crucial parameters to be considered for future optimization, which is currently missing. In this review, the performances of BES approach of biogas upgrading under various operating settings in particular fed-batch, continuous mode in connection to the microbial dynamics and cathode materials have been thoroughly scrutinized and discussed. Additionally, other versatile application options associated with BES based biogas upgrading, such as resource recovery, are presented. The three-dimensional electrode materials have shown superior performance in supplying the electrons for the reduction of CO2 to CH4. Most of the studies on the biogas upgrading process conclude hydrogen (H2) mediated electron transfer mechanism in BES biogas upgrading.
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| 3. |
- Bajracharya, Suman, et al.
(författare)
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Prime Techniques for Pre- and Post-Treatments of Anaerobic Effluents and Solids
- 2020
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Ingår i: Environmental Microbiology and Biotechnology. - Singapore : Springer Nature. ; , s. 255-289
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Several pre-treatment approaches have been explored to enhance the anaerobic fermentation kinetics and efficiency, which include thermal-alkaline treatment, free ammonia, sequential ultrasound techniques as well as grinding, and sieving. Additionally, valorization of mineralized compounds and production of reusable water can also be achieved via post-treatments. The post-treatment concept allows preserving or recovery of value-added byproducts in the form of manures, soil conditioners, and renewable energy. In this chapter, we explain the recent advancement in the pre-treatment and post-treatment of anaerobic digestate to enhance the anaerobic process and for the removal of undesirable compounds, recovery of energy, nutrients, and waste stabilization before disposal.
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